Re: [Mingw-w64-public] Strange linker error with gcc-5.1 32-bit involving 'virtual thunk'

[Edward D. <eld...@tr...>]

On 7/31/2015 6:05 AM, Ruben Van Boxem wrote:
> 2015-07-31 2:04 GMT+02:00 Edward Diener <eld...@tr...
> <mailto:eld...@tr...>>:
>
>     On 7/30/2015 10:48 AM, Óscar Fuentes wrote:
>     > Edward Diener <eld...@tr...
>     <mailto:eld...@tr...>>
>     > writes:
>     >
>     >>> Another thing is to get some hints from a .map-file.
>     >>> Add "-Wl,--print-map,--sort-common,--cref > file.map" at the
>     >>> of the link-cmd.
>     >>
>     >> I could not find any documentation regarding the linker options you
>     >> specify in the gcc documentation. Are they mingw-64 specific ? If so
>     >> where would thye be documented ?
>     >
>     > Those are not gcc options, but `ld' (the GNU linker) options.
>     >
>     > "-Wl" directs gcc to pass the following comma-separated options to ld.
>
>     To whom do I report this bug ? Does it go to mingw-64, to gcc, to the ld
>     linker on Windows ? I have shown this bug occurring through the example
>     I posted and I do not think anything I have shown is not standard C++.
>     It can be reproduced by anyone. I am not knowledgeable enough about the
>     workings of mingw-64/gcc or mingw-64/ld to be able to figure out why
>     this bug is occurring but someone knowledgeable enough should be able to
>     fix what needs to be fixed.
>
>
> I'm not sure this is a GCC bug. Does the linker error also occur when
> using static libraries, and when you dllexport the whole class as
> opposed to the functions you're explicitly defining?

I have tried neither.

> I believe this error is the same as your previous one: you're not
> dllexporting some implictly defined functions.

Which ones ? You can see the code.

> Now, if this is what MSVC
> does, perhaps GCC should be modified to follow that behaviour, but that
> is not certain at this point.

It has to be a bug in either gcc or ld using mingw-64 unless you can 
show me what is wrong with the code which produces the link errors. 
Unless you tell me that gcc/ld on Windows is incapable of 
exporting/importing individual member functions of a class rather than 
the class as a whole this is a bug somewhere in gcc/ld.